Synced photos can't be deleted directly on the iPad, instead they are removed by not including them in the next photo sync (which is why you are getting that message). There are third-party apps such as Simple Transfer which can copy photos to (and from) the Photos app (they will go into the Camera Roll album) via your wifi network (you can then copy them into new albums directly on the iPad). Or there are photo management apps such as Photo Manager Pro which have more flexibility for adding/removing photos than the built-in Photos app.
Aside from what KP is suggesting, you can combine all of the photos into one folder from which she can sync her iPad. Copy the photos from the one computer to the other computer - place all the photos that she wants to sync into one level of sub folders within the main folder that syncs for in iTunes.
The old laptop is shot. I've kept the HD and could slave it to the desktop and copy all the photos as Demo suggested. Presumably then iTunes on the desktop will sync everything and she'll have a single photo library (without duplicates). However, I she did notice that with the photos already sync'd from the laptop (before I recycled it) that they aren't well organized. Will Photo Manger Pro do a better job or organizing the photos into albums than the native iPad photo app?
You can use an app such as Simple Transfer to copy synced photos back from the iPad to a computer, but photos are 'optimised' when they are synced to the iPad, so any that you copy back may not be exactly the same as they were on the original drive - so if you can copy them off the old drive then that would probably be preferable.
I've only had Photo Manager Pro a couple of days, but it appears to have more features than Photos e.g. you can copy or move photos between albums directly in the app (Photos only allows to copy photos into albums that you create directly in the app i.e. you can't copy photos into synced albums). You can also change the order in which the photos are sorted in it e.g. ascending or descending by date, name, size, or you can put them into your own order. You can also copy photos to/from Photos with it.
Will Photo Manger Pro do a better job or organizing the photos into albums than the native iPad photo app?
Much better. Just forget the stock Photos app, it's so inferior to PMP in most respects. There's a tips & tricks-collection for PMP at http://www.iphonelife.com/blog/87/all-one-photo-viewer-roundup-70-price-drop-bes t-image-viewer (also mentioned in the AppStore description of the app); worth a read.
Another way. You can use a USB flash drive & the camera connection kit.
Plug the USB flash drive into your computer & create a new folder titled DCIM. Then put your movie/photo files into the folder. The files must have a filename with exactly 8 characters long (no spaces) plus the file extension (i.e., my-movie.mov; DSCN0164.jpg).
Now plug the flash drive into the iPad using the camera connection kit. Open the Photos app, the movie/photo files should appear & you can import. (You can not export using the camera connection kit.)
Secrets of the iPad Camera Connection Kit
Texas Mac Man wrote:
The files must have a filename with exactly 8 characters long (no spaces) plus the file extension (i.e., my-movie.mov; DSCN0164.jpg).
Are you absolutely sure "my-movie.mov" is OK? In my practice, using -'s have resulted in the files not being visible to the importer utility. (iOS 5.1.1)